Acute Tubular Necrosis

Definition

Definition of Acute Tubular Necrosis
Acute tubular necrosis or (ATN) is a medical condition involving the death of tubular cells that form the tubule that transports urine to the ureters while reabsorbing 99% of the water (and highly concentrating the salts and metabolic byproducts). Tubular cells continually replace themselves and if the cause of ATN is removed then recovery is likely. ATN presents with acute renal failure (ARF) and is one of the most common causes of ARF. The presence of "muddy brown casts" of epithelial cells found in the urine during urinalysis is pathognomonic for ATN.

Symptoms

Symptoms of Acute Tubular Necrosis
Acute tubular necrosis is classified as a "renal" (i.e. not pre-renal or post-renal) cause of Acute renal failure. Diagnosis is made by a FeNA (fractional excretion of sodium) > 3% and presence of muddy casts in urinalysis. On histopathology, there is usually tubulorrhexis, that is, localized necrosis of the epithelial lining in renal tubules, with focal rupture or loss of basement membrane. Proximal tubule cells can shed with variable viability and not be purely "necrotic".

Causes

Causes of Acute Tubular Necrosis
Acute tubular necrosis (ATN) is usually caused by lack of oxygen to the kidney tissues (ischemia of the kidneys). It may also occur if the kidney cells are damaged by a poison or harmful substance.

The internal structures of the kidney, particularly the tissues of the kidney tubule, become damaged or destroyed. ATN is one of the most common structural changes that can lead to acute renal failure.

Diagnosis

Diagnosis of Acute Tubular Necrosis
The doctor will perform a physical exam. Your doctor may hear abnormal sounds when listening to the heart and lungs with a stethoscope (auscultation). This is due to too much fluid in the body.

Treatment

Treatment of Acute Tubular Necrosis
The main goal of treatment of acute tubular necrosis (ATN) is to prevent further injury to the kidney. Extracellular fluid (ECF) volume should be assessed promptly, either on clinical grounds or by invasive means (Swan-Ganz catheter), and repletion of any deficit should be initiated promptly. The 2011 UKRA guidelines recommend optimizing hemodynamic status by appropriate fluid therapy, giving vasopressors and/or inotropes and treating any underlying sepsis.

Prognosis

Prognosis of Acute Tubular Necrosis
How long symptoms last can vary. You may make less urin for a few days to 6 weeks or more. This may be followed by a period of high urine output. This occurs because the healed and newly functioning kidneys try to clear the body of fluid and wastes.

Prevention

Prevention of Acute Tubular Necrosis

1. Promptly treating conditions that can lead to decreased blood flow and/or decreased oxygen to the kidneys can reduce the risk of acute tubular necrosis.
2. Blood transfusions are crossmatched to reduce the risk of incompatibility reactions.
3. Control conditions such as diabetes, liver disorders, and cardiac disorders to reduce the risk of acute tubular necrosis.